[COMMITTED] ada: Fix memory explosion on aggregate of nested packed array type
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From: Eric Botcazou <ebotcazou@adacore.com>
It occurs at compile time on an aggregate of a 2-dimensional packed array
type whose component type is itself a packed array, because the compiler
is trying to pack the intermediate aggregate and ends up rewriting a bunch
of subcomponents. This optimization was originally devised for the case of
a scalar component type so the change adds this restriction.
gcc/ada/
* exp_aggr.adb (Is_Two_Dim_Packed_Array): Return true only if the
component type of the array is scalar.
Tested on x86_64-pc-linux-gnu, committed on master.
---
gcc/ada/exp_aggr.adb | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
@@ -306,7 +306,7 @@ package body Exp_Aggr is
-- N is the N_Aggregate node to be expanded.
function Is_Two_Dim_Packed_Array (Typ : Entity_Id) return Boolean;
- -- For two-dimensional packed aggregates with constant bounds and constant
+ -- For 2D packed array aggregates with constant bounds and constant scalar
-- components, it is preferable to pack the inner aggregates because the
-- whole matrix can then be presented to the back-end as a one-dimensional
-- list of literals. This is much more efficient than expanding into single
@@ -8563,9 +8563,11 @@ package body Exp_Aggr is
function Is_Two_Dim_Packed_Array (Typ : Entity_Id) return Boolean is
C : constant Uint := Component_Size (Typ);
+
begin
return Number_Dimensions (Typ) = 2
and then Is_Bit_Packed_Array (Typ)
+ and then Is_Scalar_Type (Component_Type (Typ))
and then C in Uint_1 | Uint_2 | Uint_4; -- False if No_Uint
end Is_Two_Dim_Packed_Array;